Low compression/low leak down???

[SwiftTech]

A few weeks ago at the track I had nothing but problems. Timing belt jumped on the first run leaving me dead in the water. Had to get towed off the track. I was able to get it running though in the pits after borrowing a few tools to reset the belt. After I got it running though it was running a little off. I did get a couple of runs out of it, though none seemed like the mototr was running quite right. It had a hard time idling and even hicupped and back fired as I launched one run. Anyway I did a compression test and leakdown test. It only had 90-95psi compression in all 4 cyl. But also only had 2% leak down on all 4. I could hear just a little bit of air escaping from the crankcase. I have also noticed that I am only getting 10" of idle vacuum or so also. I though the cam timing might be off so I checked that and it was good. Any other ideas? Thanks.

[allmotor]

is sure sounds like you are just one tooth off on the belt. pretty easy to miss just one tooth. also after you reset the belt, did you recheck ignition timing?
question? what caused the timing belt to jump to begin with? could you have a partially sheared cam or crank key?

[drh]

Also check all vacuum lines from front to back. Under boost pressure one of your vacuum lines may have pressured itself off or loose enough to create a vacuum that may seem like other problems. Even if yu have to remove the blck harness off of the vacuun lines to be sure they are all pushe in properly. I used a bit of locktight on the vacuum line on my dytona that I found just loose enough to idle roughly send black smoke out he tail pipe.
Good Luck
DRH

[86lance]

that might explain the vacuum problem but it still doesnt explain the lower compression. Id bet the timing belt is still off

[SwiftTech]

I'll double check it again. It sure looked right but you never know. I'll also double check the ignition timing. I don't know what caused it to jump, just stopped pulling for some reason. It jumped a good bit too, like 30-40 degrees of rotation. It could have just been loose, I'm not sure. It has been about a year and a half since the motor was put into the car, but it has only been about 5,000 miles at most.